Recently, in order to realize higher performance of automobiles, a power device is used as one of semiconductor devices that support electronics for automobiles. A power device controls electric power for electronics for automobiles, and is used in various components including, for example, hydraulic valve controllers of ABS's (Antilock Brake Systems) or the like, motor controllers of power windows or the like, inverters that convert DC voltages of batteries or driving motors into DC voltages, and the like.
Current main-stream power devices use silicon (Si) semiconductors. Along with the development of hybrid vehicles and electric vehicles, next-generation power devices which consume less power and are operable under high-temperature and high-voltage conditions are now desired. Such new-generation power devices use, for example, silicon carbide (SiC), gallium nitride (GaN) or the like as described in, for example, Japanese Patent Application No. 2004-340918. These next-generation power devices have an operating frequency at the time of switching that is higher than that of conventional power devices. Therefore, when such a next-generation power device is mounted by a conventional method of wire bonding, there occurs a problem that electric noise is caused by an inductance component in the wire bonding part. In a worst case, the electric noise destroys the power device itself.
A power device, especially, a power device for electronics for automobiles is often used in an engine room, which may have a very high temperature in certain environments of use. In addition, the power device generates heat itself when being driven and thus has a very high temperature. As a result, the temperature of the power device may possibly be raised to 200° C. to 250° C. Such a high temperature of the power device influences the switching characteristics thereof, and also deforms a resin material that is used to form the power device. For these reasons, the next-generation power device is desired to have a high heat releasing characteristic. In addition, the power device is used in a limited space such as an engine room or the like, and therefore is required to be reduced in size.